Matthew J. Edlund M.D.

The Power of Rest

While You Weren't Sleeping

Disturbing results from a national study of sleep habits.

Posted Mar 19, 2016

Master-L/Shutterstock
Source: Master-L/Shutterstock

How much sleep is enough for American adults? After a long and difficult debate, the American Sleep Disorders Association finally agreed on a number last year—seven or more hours out of 24, including naps.

So how do Americans stack up?

Not too well.

In a report that appeared recently in the Center for Disease Control’s Morbidity and Mortality Weekly Report, researchers surveyed nearly 445,000 randomly selected adult Americans through both landline and cellphone. Of the group, 65.2% reported they slept seven hours or more. But fully 23% said they were sleeping six hours or less for each 24-hour period, and 11.8% said they were sleeping five or less.

Where Do They Sleep Least?

Given the huge size of this data set, the variation is large. The great non-sleeping area of the nation appears to be the Southeast, which fits with its long-established role as the “stroke belt” and the region with the nation's greatest incidence of obesity. Yet Hawaii was least sleep-friendly state with just 56.1% of residents obtaining seven or more hours a day. The “best” sleeping state turns out to be South Dakota, where 71.6% reach the threshold for satisfactory sleep. Not surprisingly, the area with the greatest concentration of “good” sleepers was the northern Midwest, where overall public health measures tend to be strong.

Who Sleeps the Least?

As one would surmise, different groups sleep very, very differently. The population cohort obtaining the least adequate sleep was the disabled—only 51% slept more than seven hours per 24. Among the unemployed, a relatively low 60.2% got the suggested required sleep.

Considering different ethnic groups, Hawaiians/Pacific Islanders, non-Hispanic blacks, and multiracial Hispanics were all around 54%, while non-Hispanic whites came in at 66.8%, with Hispanics at 65.5%.

Who slept best? Married people, with rates at 67.4%. (Divorced/separated people got adequate sleep at a rate of 55.7%.) College graduates also slept better than others, with 71.5% claiming to sleep more than seven hours per 24 hours.

Why Do People Sleep Less?

The reasons for lesser sleep are legion. Clearly sleep disorders are part of the picture, with some estimates that as much as 15-20% of the population suffers from frequent insomnia. People who weigh a lot sleep less, even if they experience no sleep disorders. Though many think predominantly overweight sleep apnea sufferers sleep too much, the majority in fact suffer from insomnia. People working multiple jobs and parents with young kids are other groups who obtain far less sleep. Certainly the quarter of the population that does shift work adds to sleepless numbers. Work, school, and parenting schedules are significant factors on a global scale.

Not for us to leave out is money. Though some political leaders may believe poor people have “greater sleep opportunity,” the truth is the opposite: The poor simply do not sleep well.

Does Anyone Sleep Too Much?

Studies show that people who sleep more than eight hours of sleep a night have higher mortality rate, but about 8% of Americans claim to sleep nine hours or more, with 3.6% sleeping 10 hours or more. The CDC report is careful to separate those who sleep longer because of illness from those who just sleep long. The authors point out that some studies of otherwise healthy people show them sleeping long with no apparent ill effects. Parsing out genetic factors versus clinical problems that have yet to become “diagnosable” makes this type of study really difficult.

Are There People Who Sleep Short or Long Hours Naturally?

Yes, lots. There are many in the population who can sleep three or four hours—or less—and perform well, just as there are long sleepers who function very admirably. When it comes to total sleep times, genetics is powerful. Both amount of sleep and time of sleep differ greatly in the general population. Certainly there are "functional hypomanics" who are notably energetic and require little sleep. However, most sleep clinicians would argue that those who can healthily sleep less than five hours are perhaps 3-4% of the population—and in this survey 11.8% report themselves sleeping less than that.

Why Should We Care About Sleep Duration?

It’s a big factor in overall health. When it comes to human survival, we regenerate or we degenerate. When people sleep less than six hours—and we’ve got close to a quarter of the “healthy” US population claiming that—they are more prone to heart disease, stroke, obesity, diabetes, and depression. They have higher blood pressure. They die earlier. They get colds more often. They’re crankier. They’re more prone to poor moral decisions.

Sleep may be a little less than one third of life. But it’s required for survival and health. And at least a third of the country does not appear to get enough.